UNHAPPY RETURNS: Carmelo Anthony walks off the court during the second half of last night’s 108-101 Bulls victory at the Garden. The Knicks fell behind early and Anthony’s 39 points weren’t enough. Photo: N.Y. Post: Charles Wenzelberg

This trashy trash talk is about a lot more than cereal, and Anthony and the Knicks must dedicate themselves again to the main course. They need to regain their sizzle — and it starts with Anthony. It always starts with the superstar.

He needs to focus his attention on hurting his opponents the best way he can and that means beating them on the court, not lurking around the opponent’s team bus as he did with the Celtics’ mouthy Kevin Garnett. Anthony’s costly one-game suspension destroyed the Knicks for a second straight game last night as coach Mike Woodson’s slumping team was beaten by the Bulls, 108-101 at the Garden.

Anthony scored 39 points, but most came when the Knicks were down by a couple of touchdowns. He missed his first seven shots and 10 of his first 11.

When it was over he was asked what he learned from this entire experience, and his answer offers hope that perhaps things will change for the best with Anthony.

“I definitely hurt my team, we had a chance to win that basketball game,’’ Anthony said. “But for the most part, things are said on the basketball court. I accept that. I accept trash talking. I accept that. Just like I said: There are just certain things that you don’t say, that push the button.’’

But he’s the Knicks star — and his button will be pushed.

Just wait until the Knicks play the Celtics in Boston in 12 days. Expect boxes of Honey Nut Cheerios to be everywhere. Anthony is going to have to get tougher every step of the way. Teams will try to throw him off his game.

Anthony must change. It’s part of growing up. It’s part of being a target. Opposing teams know if they get in Anthony’s head they have a much better chance to beat the Knicks. With Anthony missing all those early shots, the Knicks’ fate was sealed against the Bulls, who play the kind of team defense the Knicks can only dream about at this point.

Remember when the Knicks were 10-0 at home? Well, with this loss, they are 3-5 at the Garden since those heady days.

Garnett set off this entire Melo sideshow, according to an Internet report, by allegedly telling Anthony that his wife La La Anthony “tastes like Honey Nut Cheerios.”

La La followed up by tweeting: “Not for nothing, but we ALL deserve a check or some free cereal 4all the publicity we’ve given Honey Nut Cheerios! LOL #cantbelieveeverything”

It’s a TMZ sports world we’re living in these days, we know that, but it still comes down to the scoreboard. That is where Anthony can get the last word. He has to find a way to be bigger than what is thrown in his direction and play with stronger focus and purpose from the start.

The Knicks are 5-8 over their last 13 games and miss Raymond Felton (fractured finger) as Jason Kidd continues to turn to dust as the point guard. The veteran was 0-for-6 with no assists.

Worse than that, the Knicks were soft at the start.

“We can point the fingers at a lot of things,’’ Woodson said. “First with me. I’m the coach I’ve got to get us out of this rut. I don’t like the way we’re starting ball games because that’s been an indication of how we’ve played throughout the course of the game.’’

Before the game, Woodson bristled when he was asked if Chicago’s Tom Thibodeau has outcoached him, but that is exactly what has happened as the Bulls have beaten the Knicks for the third straight time. The Knicks know what opponents are trying to do against them in both words and deeds.

Now is the time to adjust and be strong, before it is too late. It all starts with Anthony.